1. Field of the Invention
The present invention relates to a resin composition which is suitable for the production of an automobile relay box and an automobile relay box comprising the same.
2. Description of the Related Art
Recently, automobiles are highly installed with electronics and include many electrical parts. The electrical parts are made of various plastic materials to reduce their weights and simplify their production steps. In particular, a material of a relay box is required to have good heat resistance, solvent resistance and mechanical strength. Further required are flowability and dimensional stability to mold a relay box having a complicated shape with good dimensional accuracy. As a material which satisfies these properties, 6,6-nylon is widely used. 6,6-Nylon is one of crystalline engineering plastics and is excellent in flowability, heat resistance and solvent resistance. However, due to its water absorption property, it suffers from decrease of mechanical properties and dimensional change. In addition, in a cold season, it is cracked by calcium chloride which is sprayed on a load as an antifreezing agent.
Needs for weight saving of the automobile are increasing, and it is desired to provide a material which is light and satisfies the properties necessary for the automobile relay box.
To remove the above defects of 6,6-nylon, it is proposed to compound polyphenylene ether in 6,6-nylon (cf. Japanese Patent Publication No. 41663/1984). However, when an automobile relay box is made of a resin composition comprising 6,6-nylon and polyphenylene ether, the decrease of mechanical properties or dimensional change caused by water absorption are prevented, but the moldability of 6,6-nylon is decreased, so that the flowability and mold releasability of the resin composition are insufficient for the production of a relay box having a complicated shape. In addition, weld strength of the molded relay box is decreased. In view of recyclability of the resin composition which is required for the automobiles in these years, the resin composition comprising 6,6-nylon and polyphenylene ether is unsatisfactory.
Accordingly, it has been highly desired to provide a resin material which is light and satisfies the properties required for the automobile relay box such as heat resistance, solvent resistance, mechanical resistance, weld strength, moldability, in particular, flowability and mold releasability, weathering resistance and recyclability.